Switch operating mechanism



may 26, 1936. F. H, COLE 2,041,902

I SWI'LCH OERATING MECHANISM I Filed July 28, 1932 4 Sheets-sheet 2 Mfy 26, F. H COLE SWITCH OPERATING MECHANI SM Filed July 28, 1952 4 Sheets-Sheet 5 v WW1/@H6556 26, maa F H, OLE y ammore SWITCH OPERATING MECHANISM Filed July 28, 1932 4 sheets-sheet 4 Patented May 26, 1936 UNTED STATES PATENT OFFICE SWITCH OPERATING MECHANISM Application July 28, 1932, Serial No. 625,429

8 Claims.

This invention relates to the operating mechanism and tripping means for circuit breakers in general and more particularly for circuit breakers of high voltage or high current interrupting capacity.

It is one of the objects of the present invention to provide a switch operating and tripping mechanism wherein a very rapid tripping action is obtained. In the particular embodiment of the invention herein illustrated this is accomplished by providing an improved tripping unit separate from the operating unit and arranged to merely bear against the operating unit to retain it in its operated condition. When the tripping mechanism is released it is not drawn with the operating unit; hence the delay incident to the inertia necessarily present in the various parts is avoided. The tripping unit is normally locked in its operative position and is arranged to be released by an electromagnet cr other means. Upon release of the locking arrangement for the tripping means the operating mechanism forces the tripping means to its released position. The tripping magnet need only supply the energy necessary for unlocking the tripping means while the operating mechanism supplies the energy necessary for actually moving the tripping means to its released position. Thus although the tripping means may be arranged to resist a comparatively great force tending to operate the switching mechanism to its open position yet an almost negligible force is required to release the tripping means.

The circuit breaker operating mechanism of the present invention is provided with an operating handle for manually operating the same. The arrangement is such that the handle occupies the same position when the mechanism is in its switch closed position as it does when the mechanism is in its switch open position. This position of the operating handle is termed the norma position. To close the circuit breaker the operating handle is moved from its normal position to its switch closed position, which results in a closure of the switch, and is then returned to its normal position. The return movement to the normal position does not result in a release of the mechanism. Electromagnetic tripping means is provided for tripping a latch that holds the mechanism in its closed position, such tripping means being eiective to trip the mechanism regardless of the instantaneous position of the operating handle. This is known in the art as a trip free switch operating mechanism. I provide additional means for tripping the circuit breaker mechanism responsive to a reverse movement of the operating handle from its normal position. Thus when the operating handle is in its normal position the mechanism may be in its switch closed position or in its switch open position. If the mechanism is in its switch open position then a movement of the handle in one direction from the normal position will result in a closure of the mechanism. If the mechanism is already in its closed position then an initial reverse movement of the operating handle from its position will result in a tripping of the mechanism.

It is a further object of the present invention to provide a simple arrangement whereby two separate circuit breakers may be selectively operated from a single operating shaft and interlocked to assure the opening of one breaker prior to the closure of the other. In the event that the circuit breaker to be opened fails to open, the arrangement is such that the other circuit breaker is prevented from closing. This is particularly desirable in certain circuit arrangements. Two circuit breakers may be provided for selectively connecting a line to one or another of two busses. If both circuit breakers are closed at the same time the line will be connected to both busses, hence the two busses will be interconnected. This, in some instances, is undesirable. The two busses may be at somewhat different potentials as, for instance, a main bus and a regulator bus that is fed from the main bus through a regulator. The voltage of the regulated bus may be somewhat above or somewhat below the main bus voltage and if the two busses are interconnected by the twocircuit breakers the resulting difference in potential will produce a large flow of current through the short circuiting connection, with the result that both circuit breakers would trip. Also the two busses might represent two different sources of power as a main and a reserve source, where said sources are not synchronized with respect to one another. By the present arrangement the operation of the switch closing lever to close one circuit breaker necessarily trips the other circuit breaker and if the other circuit breaker fails to trip then the complete closing of the rst circuit breaker is prevented.

The attainment of the above and further objects oi the present invention will be apparent from the following specication taken in con-- junction with the accompanying drawings forming a part thereof.

In the drawings:

Figure 1 is a longitudinal sectional view of the switch operating mechanism, said View being taken along the line I-I of Figure 2;

Figure 2 is a front view of the mechanism;

Figure 3 is a side View of the tripping mechanism, said view showing the mechanism in the locking position;

Figure 4 is a view similar to Figure 3 and showing the mechanism upon energization of the tripping magnet and before the release of the mechanism;

Figure 5 shows the tripping mechanism as it is being restored to its locking position;

Figure 6 is a sectional view taken along the line 6--6 of Figure 2;

Figure 7 is a fragmentary diagrammatic sectional view showing two circuit breaker operating mechanisms connected together for operation from the same operating shaft and interlocked to prevent simultaneous closing of both circuit breakers; and

Figure 8 is a fragmentary sectional view taken along the lines 8--8 of Figure 7 and showing a locking arrangement for the operating shaft.

Reference may now be had more particularly to Figure 1 of the drawings which shows the mechanism in its normal switch closed position. The

' mechanism is enclosed in a suitable metallic housing indicated in general by the reference numeral I. A bell crank 2 is pivoted about a pivot pin 3 held by a pair of bracket arms 4--4 of the housing. rThe arm 5 of the bell crank 2 is pivotally connected at B with a switch operating link 1. When the switch is in its closed positions the link 1 exerts a continuous pull to the left as seen in Figure 1 to urge the bell crank to its switch open position. A toggle link I0 is pivoted to the arm Il of the bell crank 2 by means of a pivot pin I2 and is pivotally connected to a toggle link guide I3 by means of a pin I4. A guide link I6 is pivoted at one end about a stationary pivot I5 and at its other end is pivotally connected to the toggle link guide I3 by means of a pin I1. A holding latch 2D is pivoted about a stationary pivot 2| and has pivoted thereto a link 22 about a pivot 23. The opposite end of the link 22 is pivoted to the pin I1. The toggle link guide I3 carries a roller 24 at one end thereof, said roller resting upon the holding latch 20. The latch 20 is biased in a clockwise direction by a spring 26 and is held in the extreme position as shown in Figure 1 by a stop ringer 21 abutting against a stationary stop 28. An eye bolt 3D that is secured to the core 3| of an operating solenoid is also pivoted about the pin I1, said eye bolt having an enlarged eye for receiving the pin and permitting a limited amount of side movement of the pin with respect to the eye bolt. A tripping bell crank 32 is pivoted about a stationary pivot 33 and carries at its end a roller 34 that bears against a portion 35 of the link I0, said portion 35 constituting an extension of the link I0 projecting beyond the knuckle I4 of the toggle formed by the toggle link I0 with the toggle link guide I3. Under normal conditions the tripping bell crank 32 is locked in the position shown in the drawings, being held against rotation about the stationary pivot 33 by suitable mechanism to be more fully set forth as this description proceeds. As long as the trip crank is locked in the position as shown it maintains the knuckle of the toggle comprising the members I0 and I3 against breaking, that is, it holds the toggle from collapsing under the downward force exerted on the pin I2 by the arm II of the bell crank, which arm is being urged in a clockwise direction by the pull on the switch operating link 1. The pin I1 is urged downwardly but is locked against downward movement by the holding latch 20 that supports the roller 24. The force of the roller 24 on the holding latch 2U is such as to tend to turn the same about the pin 2| in a clockwise direction, which movement is prevented by the stop 21-28. It is therefore apparent that as long as the tripping bell crank 32 is locked in position the toggle mechanism is also locked in position.

Reference may now be had more particularly to Figures 3 to 5 which show the tripping bell crank and the manner of releasably locking the same. The bell crank lever 32 includes an arm 32a integral with the portion 32 thereof so as to move as a unit therewith. A trip latch 38 is pivoted to the arm 32a by a pivot pin 39 and has a trip latch guide 43 pivoted thereto at 4I. The opposite end of the trip latch guide is pivoted to a stationary pivot 42. A trip latch cam 44 is pivoted about the same pin 42 and carries at one end a roller 45 that lies over the end of the trip latch 38. As long as the trip latch cam 44 is in the position shown in Figure 3 the bell cranks 32--32a cannot rotate about the pin 33 in a counterclockwise direction as seen in Figure 3 (clockwise as seen in Figure l) since the roller 45 holds the end of the trip latch against upward movement. It 30 is also apparent that no reasonable amount of force exerted on the trip latch 38 by the pin 39 tending to move the trip latch to the right as seen in Figure 3 will be eiective to release the trip latch since this force acts on the trip latch cam 44 radially with respect to its center of rotation 42, rather than tangentially. A trip link 4B is pivoted at its lower end to the trip latch cam 44 by means of a pin 41, said link being adapted to be actuated by a tripping electromagnet 48 which, upon energization, raises the trip link and rotates the trip latch cam 44 in a clockwise direction as seen in Figure 3 to move the roller 45 clear of the trip latch 38.

An explanation will now be given of the mode of operation of the apparatus thus far described. Assume that the tripping magnet 48 is energized to pull up on the trip link 46 thereby moving the trip latch cam 44 to its released position, as indicated in Figure 4. The tripping bell crank 32 is now free to rotate about the pin 33. The pull on the switch operating link 1 is transmitted through the bell crank 2 to the toggle link I0 which toggle link at its extended portion 35 exerts a force on the roller 34. This force has a small component tending to rotate the tripping bell crank 32 clockwise as seen in Figure 1 (counterclockwise as seen in Figure 3). Since the bell crank member 32 is now not locked in position this force moves the bell crank, thereby permitting the knuckle I4 of the toggle IB-I3 to break. The center of the pin I4 therefor now moves to a position such as indicated at I4a and at the same time the center of the pin I2 moves to a position such as is indicated at the point I2a. This permits the switch operating link 1 to actuate the switching mechanism to its open position. Attention is called to the fact that this operation is entirely independent of any movement of the pin I1. Once the tripping bell crank 32 is released it is necessary for only the toggle links ID and I3 to move to their open position in order to permit opening of the switch. The link I3 rotates about the pin I1, bringing the axis of the roller 24 to the point 24a.

the operating magnet happens to be energized at this time, the solenoid core 3| remains in the position shown and therefore the guide link I6, the holding latch 20, and the holding latch guide 22 remain in the position shown in the drawings. The switch operating link 'I has, however, operated to trip the circuit breaker. When and if the electromagnet or solenoid 55 is deenergized the core 3| drops of its own weight to the switch open position. As the eye bolt 3U moves downwardly, the holding latch guide 22 moves the latch 20 in a counterclockwise direction, thus permitting the roller 24 to pass downward under the latch 20. At this time the pin |4 moves from the position |4a to the position |4b while the pin I1 moves to the position lla and the pin 24 moves from the position 24a to the position 24h. A bumper spring 49 limits the extent of the downward movement of the eye bolt 39 and also acts to cushion the fall. This movement of the mechanism conditions the linkage for subsequent operation and is known as the resetting operation. The bell crank 32 drops back to the locking position shown in Figure 1, and. the trip latch 38 (Figure 3) returns to the position shown in Figure 3. If the tripping magnet 48 is deenergized at this time, the trip latch cam 44 is in the position shown in Figure 3. If the trip latch cam 44 is returned to its initial position by the deenergization of the tripping magnet 48 before the trip latch 38 has been returned to its original position the tapered end portion 56 of the trip latch will exert a force on the roller as the trip latch falls to its normal position, and will force the trip cam clockwise about the pin 42 until the trip latch reaches its normal position. Thereafter the trip latch cam resumes the position shown in Figure 3, dueto the fact that its center of gravity is to the left of the axis of the pin 42 as seen in Figure 3. If desired, this return movement may be aided by a spring biasing the trip latch cam in a counterclockwise direction.

To reclose the circuit breaker it is only necessary to raise the solenoid core 3|. This may be done manually, as through a link 56, or by energizing the solenoid 55. As the eye bolt is raised,

the holding latch guide 22 moves the holding latch 20 counterclockwise so that the latch is clear of the roller 24. As the roller 24 moves above the surface 58 of the latch 26 the spring 26 forces the latch clockwise to bring the latch holding portion directly under the roller 24. For this purpose the guiding link 22 is provided with an enlarged slot through which the pin 23 passes. Once the roller comes to rest on the latch 29 the mechanism is locked in position and cannot be withdrawn even though the operating magnet is deenergized or the manual actuating force is released.

In Figure 6 there is shown the manual operating means and interlocking means for the mechanism of Figure 1. A rotatable operating shaft 60 has a crank 6| suitably secured thereto. The end of the crank 6| is provided with a pin 62 that rides in a slot 63 in the link 56, which is shown in its normal switch closed position. When the switch mechanism is in its normal open position and the core 3| of the operating magnet (Figure 1) has dropped, the link 56 is also dropped until the upper portion of the slot 63 lies over the pin 62. To close the switch the shaft 60 is rotated in a clockwise direction. The pin 62 forces the lever 56 upwardly, thereby forcing the solenoid core upwardly, to move the mechanism to the position shown in Figure 1. If the shaft 60 is Ythen permitted to remain in the switch closed position the link 56 will be in a position turned a few degrees counterclockwise about the pin 65. If the shaft is returned to its initial normal position as shown in Figure 6 the link 56 pivots about the pin 65 to the position shown in Figure 6 while the pin 62 rides in the slot 63. When the switch mechanism trips and the eye bolt 3D (Figure 1) drops to its switch open position the link 56 drops, said link being guided by the pin 62 riding in the slot 63.

It is to be noted that when the switch mechanism is in its closed position the pin 62 is somewhat above the bottom of the slot 63. This permits a limited counterclockwise movement of the crank 62 when t-he mechanism is in its switch closed position. A tripping lever 68 is keyed to the shaft 69 and cooperates with a trip cam 69 which is pivoted about a stationary pivot 10 and is pivotally connected with a trip rod '1| by means of a pin l2. When the shaft 69 is in its normal position the trip cam 69 is in the position shown. Upon counterclockwise rotation of the shaft 60 the lever 68 engages the cam surface 12 and forces the trip cam 69 upward about the pin 19 as a center. As the trip cam 69 rises it raises the trip rod 1|. The trip rod extends upwardly to the movable armature of the tripping magnet 48 and actuates this armature to actuate the trip link 46 in the same manner as this link is actuated by the energization of the tripping magnet 48, thereby releasing the trip latch cam 44 to trip the circuit breaker. It is thus seen that upon clockwise rotation of the shaft 69 from its normal position the switch mechanism will be operated to a closed position, whereas upon the initial counterclockwise rotation of the shaft from its normal position the switch mechanism will be tripped.

In Figure 7 I have illustrated, diagrammatically, an arrangement whereby two switch operating mechanisms of the type above described may be selectively operated by the same shaft 69. The unit 86 represents the mechanism previously described, the mechanism 6| being arranged so that upon downward movement of the handle 15, into the plane of the paper, the shaft 69 is rotated clockwise as seen in Figure 6 to operate the crank 6| and actuates the mechanism to its closed position. The switching unit 8| may be identical to the unit 86, differing only in that the crank Bla, which corresponds to the crank 6|, is on the opposite side of the shaft, hence the shaft 60 must be rotated in the opposite direction, that is counterclockwise as seen in Figure 6, to raise the pin 62a, which corresponds to the pin 62 of Figure 6, to operate the mechanism. In such an arrangement it is of course obvious that the link 56a corresponds to the link 56 of Figure 6 but extends from the pivot 65 on the right hand side of the mechanism rather than on the left hand side as shown in Figure 6. In the unit 8| the trip cam 66a, which corresponds to the trip cam 69 of the unit 86, is located on the opposite side of the shaft. In other words, the unit 8| differs from the unit 89, as illustrated in Figure 6, only in that the position of the link 56a and the cam 69a have been reversed with respect to the positions of the corresponding members as shown in Figure 6.

From the description thus far given it is apparent that when the shaft 66 is rotated to close the mechanism 8| the initial rotation of the shaft 60 brings the pin 62 to the bottom of the slot 63 of the mechanism 80 and at the same time the lever 68 operates the cam 69 to bring about a,

direction as seen in Figure 6.

tripping of the switch mechanism 80. Thereafter the link 56 drops to permit continued rotation of the shaft 60 to close vthe switch unit 8l. After the switch unit 8l has been closed the shaft 66 is returned to the position shown in Figure 6. If it is later desired to operate the switch mechanism the shaft 6l] is rotated in a clockwise Upon the initial rotation of the shaft 66 clockwise as seen in Figure 6 the pin 62a travels downward in the corresponding slot in the member 56a and at the same time the lever corresponding to the lever 68 brings about the operation of the trip cam 69 to trip the switching mechanism 8l. In this same connection it should be `noted that if the tripping mechanism of either unit 80 or 8| should fail to operate yto release the unit from its switch closed position it will not be possible to pull downward upon the corresponding link 56 or 56, and therefore this link, acting through the pin 62,'will lock the corresponding cranks 6I and 6 Ia against rotation and thereby positively prevent the closing of either circuit breaker while the other breaker remains in its closed position. By the present arrangement there is provided a simlple and effective locking arrangement for insuring against the mechanical closure of one circuit breaker while the other is closed. Electrical closure of the two circuit breakers may be prevented by providing electrical interlocks in the circuits of the two operating magnets so that a closure of one breaker introduces a gap in the operating circuit of the operating magnet of the other breaker.

It may be desirable to lock the mechanism against unauthorized closure and for this purpose I have provided an arrangement such as is shown in Figure 8. In this connection it should be noted that the apparatus must always be left in such a condition as to permit prompt manual tripping of the mechanism since the preservation of life or property may be dependent upon the prompt manual tripping of the circuit breaker. Therefore it is inadvisable to lock the mechanism to prevent tripping of the same without a key. However, the mechanism may be safely locked against re-closure without the use of a key. This is obtained by providing a locking arrangement which permits only a limited rotation of the shaft 6D, that is, sufficient to operate the cam 69 or the cam 69a. For this purpose the shaft 60 is provided with a locking cam keyed thereto and cooperating with a latch 86 pivoted about a pivot B1. The latch is provided with a tongue 88 that extends into a slot 89 in the member 85 and prevents rotation of the shaft 68. If the latch 86 is slightly elevated, the tongue 88 clears the slot B9 and rides in a slot 89YL in the member 85. When the tongue 88 is in the slot 89e it permits a limited amount of rotation of the shaft 60 in either direction from its normal position, an amount sufficient to trip either cam 69 or 69a (Figures 6 and 7). For the continued operation of the shaft 60 it is necessary to further raise the latch 86. This may be prevented by any suitable locking arrangement, as by means of a hinged bolt that is adapted to be padlocked to a cooperating lug spaced above the latch 86. The locking bolt 95, when padlocked, is spaced from the latch 86 an amount suflicient to permit movement of the latch to cause the tongue 88 to clear the slot 89, but insufficient to clear the slot 89a. 'I 'o permit a further movement of the latch 86 it is necessary to release the hinge bolt, an operation that requires the unlocking of the padlock. It is of course to be understood that any other desirable locking arrangement may be provided.

In compliance with the requirements of the patent statutes I have herein shown and described a preferred embodiment of my invention. It is however to be understood that the invention is not limited to the precise arrangement herein shown, the same being merely illustrative of the general principles of the invention. What I con- Sider new and desire to secure by Letters Patent isz- Y 1. In combination with two sets of switch operating mechanisms each of which includes individual tripping means, a common operating member operable in one direction from a normal inoperative position for operating one mechanism to switch closing position and in the opposite direction from said normal position for operating the other mechanism to switch closing position, and means responsive to the operation of the operating member in one direction from said normal position for rst actuating the tripping means of the mechanism that is actuated by the opposite operation of the operating member prior to operation of the switch closing mechanism.

2. In combination, a first switch controlling mechanism, tripping means therefor, a second corresponding switch controlling mechanism, corresponding tripping means therefor, a common operating member for actuating said rst tripping means prior to operation of said second switch controlling mechanism, and releasable means providing for actuation of both of said tripping means while preventing movement of either of said mechanisms to switch closing position.

3. In combination, a pair of switch controlling mechanisms, individual tripping means therefor, a rotatable shaft common to both said mechanisms, means carried by said shaft providing for limited rotation of said shaft to operate both of said tripping means while preventing switch closing movement of either of said mechanisms, and means for releasing said rotation limiting means to provide for switch closing movement of either one of said mechanisms subsequent to operation of said tripping means for the other of said mechanisms.

4. In combination, a pair of corresponding switch operating mechanisms, one of the said mechanisms being normally in switch closing position, identical individual tripping means therefor, a common operating member disposed between said individual tripping means, and means actuating said member to operate the tripping means of the closed one of said mechanisms prior to initial movement of the other one of said mechanisms toward switch closingr position, said means being adapted to operate both of said tripping means independently of operation of either of said members toward switch closing position.

5. In combination, a pair of switches, separate switch operating mechanisms for each of said switches, individual tripping means for each of said switches, a common actuating shaft for said switch operating mechanisms and said tripping means, means carried by said shaft and operable upon continued rotation of said shaft in either direction from normal inoperative position for first tripping one of said switches and subsequently moving the opposite switch operating mechanism toward switch-closing position, and 75 releasable means for limiting rotation of said shaft to provide for operation of each of said tripping means while preventing operation of either of said switch operating mechanisms.

6. In combination, a pair of switches, one of said switches normally being in closed position, a shaft common to both said switches, spaced individual tripping means carried by said shaft for tripping each of said switches, individual switch operating means on said shaft adjacent each of said tripping means for closing each of said switches, and means for preventing continued rotation of said shaft for closing one of said switches until the other of said switches has been opened by its tripping means, said shaft being normally maintained in inoperative position and initially rotatable in either direction to operate a preselected one of said tripping means.

7. In combination, a pair of switches, individual tripping means for each of said switches, a shaft common to both said switches, and operating means on said shaft normally disposed in an intermediate inoperative position and movable in opposite directions from said position to rst rotate said shaft to operate the tripping means of one of said switches and to subsequently close the other of said switches during continued movement of said shaft in each direction from said intermediate position.

8. In combination, a pair of switches, one of said switches being normally closed, switch operating mechanisms therefor, tripping means for each of said switches, a common operating mechanism movable in one direction from a normal inoperative position to actuate the tripping means `for said one of said switches and upon continued movement in the same direction to actuate the switch operating mechanism for closing the other of said switches, and releasable means for preventing said continued movement.

FRED H. COLE. 

